Are any of the addons listed on this page required?
No. all addons listed on this page are optional. You can choose to use all, some, or none of them in an FA ArmA 3 session.

Can I use any client-side addon in an FA session?
No. We are currently white-listing addons on the ArmA 3 server. Only the addons listed and linked to in this post are permitted (the server will not let you connect with other addons).